Let me see if I can recall some tasty 2014 improvements for you....
You had already mentioned the folding mirrors being added to the Tech package in late 2013 (Nola_Mike). The driver window control button cluster also changed with the power folding mirror button added in the top center to actuate the folding mirrors.
In 2014....
The Air Suspension was upgraded with a height adjustment feature that remembered previous activation locations via the GPS and automatically adjusted height if your location was revisited and correct (slow) speed were attained.
In Late September, AutoPilot hardware was added to the model S, a camera in front on top windshield and a radar in the front lower grill and sonar sensors in the rear bumpers and far outside front bumpers.
Also TACC Tesla Adaptive Cruise Control and Lane departure sensors and speed limit recognition and warning as part of the Tech Package. This change prompted the control stalk to change slightly.
Optional Next Gen (Recaro OEM) Seating available in the P85D in late 2014. However unanticipated popularity and demand of this option caused many P85D's to be shipped without them installed. They will be retrofitted at a later date. The P85+ Performance Seats with the red piping and alcantara panels were removed from availability at the same time.
The paint Colors Metallic Brown and Green removed from availability in late 2014.
The Color Metallic Grey changed in mid 2014 to a somewhat darker and blueish tinge.
The design studio used to offer front end protective wrap as an option, however this was dropped in mid to late 2014.
Lacewood Interior dash finish removed from availability in late 2014.
As mentioned by Cyclone, the black alcantara headliner was added as an option in mid 2014, and this option
also added alcantara to the front edge of the dashboard. Choosing premium interior deleted non-alcantara
headliner as a choice option in the design center.
Premium Interior Illumination (LEDs) were moved from a stand alone option, and moved into the Premium Interior Option package.
Parking Sensors which were a stand alone option were moved into the Tech Package in Mid 2014.
The P85 (BerTEX) and P85+ models were dropped from availability and replaced with the dual motor P85D as the Tesla Model S premium performance 691HP offering in late 2014. The frunk on the P85D lost some space where the front motor resides and the frunk latching mechanism was changed.
The P85D was the first S I saw that had new metal door sill plate inserts in the interior door area (not sure if the S60, S85 or S85D will have these, time will tell, the sill plates have never been mentioned in the Design Studio) (Note: there were a few P85+'s made near the end of their production which have all the sensors and cameras and such for the autonomous driving features, I predict that these few P85+ will be highly prized in the future)
The rear door hinges were redesigned for wider opening and easier entry to the rear seats.
The long awaited Optional Tesla Center Console, in the accessories section of the TM website began shipping in Piano Black trim only.
Additionally, the once optional Yacht Flooring in the center area became standard in mid to late 2014 where before it was a stand alone option.
Heated steering wheel added in very late 2014 as a new component of the Cold Weather Package however this
fact was not really officially announced in the design studio until mid January 2015.
The brake actuator was changed in late 2014 for a newer electronic version which was necessary for future Autonomous Driving.
The S85D could be ordered in late 2014 but would not ship until late February of 2015.
In late 2014 two sets of snow tires and wheels and TPMS sensors were added as a design center option, in 19" and 21".
New version and manufacturer of the tire pressure sensors TPMS, replaced the previous sensors in late 2014. (note to all ordering used wheels, the "old" TPMS sensors apparently do not work on the new cars, sadly. You can order the new version TPMS sensors from your SC).
Not sure about this but I have heard that the self presenting door handle mechanism was redesigned some time in early 2014. Also I think
the cabin temperature sensor was moved or modified??
Internationally, a Right Hand Drive model of the S was introduced in the UK in June of 2014 and Hong Kong in September of 2014 and
supposedly in Australia in December 2014.
There were many firmware upgrades during 2014 which the firmware WIKI aptly illustrates.
I am sure there are some other changes which I am not aware of that others may embellish upon as my memory wanes....